Conservatives on the shore, such as those who coalesced in a 2006 run for Talbot County Central Committee seats under the nickname "Rockfish Republicans," view the environment as a cross-over issue affecting both the economy and culture of the region.

"It's a split in the Republican Party," said Dirck Bartlett, a Talbot County Councilman who won his seat on a pro-environment, anti-sprawl platform. "There are environmental Republicans, and there are pro-business and pro-growth Republicans."

The race between state Sen. Andy Harris, R-Baltimore County, and Eastern Shore local Frank Kratovil, the Democratic Queen Anne's state's attorney, could be decided by that schism if Kratovil is able to siphon off enough pro-environment Republicans to offset Harris' appeal to business-minded voters.

Kratovil's efforts picked up momentum earlier this month with the key endorsement of incumbent Congressman Wayne Gilchrest, R-Kennedyville, who lost to Harris in the primary.

"I think the Republicans who supported Gilchrest in the primaries, will now be able to support Kratovil. I agree with him on the issues," said Anne Kimberly, a lifelong Republican from Easton.

"The fact that moderate Republicans on the Eastern Shore are thinking about joining Kratovil is important," said Michael Cain, director of the Center for the Study of Democracy at St. Mary's College. "The Eastern Shore has a tendency to vote for its own . . . and Kratovil lives there."

The shore makes up 57 percent of the district, according to the state's Board of Elections. If voters like the environmental Republicans defect to Kratovil, they could tip an election that observers now say favors Harris.

The big question for Kratovil supporters, said Cain, is how conservative Democrats in the district really are. "Are they willing to switch to the Republicans?"

Two other Eastern Shore Republicans, Roy Crow and Jack Cole, the respective presidents of the Kent and Caroline County boards of commissioners, endorsed Kratovil the week before Gilchrest, saying he was on the right side of environmental issues and understood the "Eastern Shore philosophy."

Harris, who lives on the Western Shore, has made the environmentally friendly choice in only 9 percent of his votes in the Maryland legislature, according to the League of Conservation Voters.

Skepticism about the stewardship Harris would bring to this peninsular society, surrounded by endangered waters and quilted in working farmland, if elected to Congress is cemented by big supporters, like the Club for Growth, which gave his campaign $246,940 during the primaries.

"The Club for Growth is constantly pushing for—exactly what their title says—growth," said Jay Falstad, the president of Republican Environmental Alliance, a political action committee that will not fund a Democrat, but wants to make explicit its lack of support for Harris. "One of the things that always aggravated me was that Harris entered this race saying he was the only conservative in this race.

"Embedded in that is the word 'conserve,' and I don't think Harris has an understanding of what that word means," he said.

"The Republicans, in fact, are far less worried about protecting the bay than we think they ought to be," said Bob Welte, a Rockfish Republican who lost his race for the central committee, and who is undecided in the current election. "No one I talk to will say the health of the bay isn't the most important thing for people who live near the bay."

Welte added, "Ironically, some of the worst offenders on the bay are some of the people who need the bay to make a living."

Those voters, and many others who subsist on small businesses or thrive on the district's accelerating development, are more likely to be wooed by the economic platforms of conservative candidates like Harris, regardless of their party affiliation.

And Democrats have crossed party lines before. While they hold a slight edge in total registration, the district's congressional seat has been held by a Republican for 18 years.

To make a dent in the election, the defecting conservationist conservatives will have to outnumber Democrats who believe a candidate like Harris will keep them in business through a tough economic period.

Despite the shore's environmental protectionism that disdains sprawl and frets over a changing way of life, Harris said he votes to protect the traditional industries of the Chesapeake Bay region, including farming, poultry and the iconic Eastern Shore watermen.

"If I think (environmental legislation) is going to hurt the local economy, I am very hesitant," he said in an interview after a news conference announcing the endorsement of the National Federation of Independent Businesses in Easton Tuesday.

Many of the 1,200 NFIB members in the district depend on those historic industries for their livelihood, said Sharon Sussin, a spokeswoman for the group.

Harris also said Maryland shouldn't go it alone while other states and the District of Columbia continue to drain pollution into the Chesapeake. "We should not be placing Maryland industries at an economic disadvantage compared to other states," he said.

Other officials in his would-be district agree. "I don't think there has to be a natural contentiousness between the two, environment and development," said Maryland Delegate Richard Sossi, a Republican who represents four shore counties.